1. Field of the Invention
The present invention relates to an inductance-capacitance (LC) element capable of attenuating a predetermined frequency band and used either as part of a semiconductor or other device, or as a discrete element, and a method for manufacturing such a semiconductor device and LC element.
2. Background Art
The rapid advancement of electronics technology in recent years has brought about the use of electronic circuits in an increasingly broad range of fields. Therefore, stable operation of these electronic circuits is sought without being affected by external conditions.
However, these types of electronic circuits are directly or intermittently subject to the incursion of external noise. Consequently, a problem exists whereby operating error is caused in electronic products using these electronic circuits in not a few cases.
In particular, there are many cases of using switching regulators as electronic circuit DC power supplies. As a result of transient current produced by such operations as switching, and by load fluctuations arising from switching operation of utilized digital ICs, noise having many frequency components is often produced in the switching regulator power supply line. This noise is conveyed via the power supply line or by radiation to other circuits in the same product, giving rise to such effects as operating error and impaired signal to noise ratio, and in some cases even causing operating error in other nearby electronic products.
Various types of noise filters are presently being used with respect to electronic circuits in order to remove this type of noise. In particular, since a great many electronic products of numerous types have come into use in recent years, the restrictions in regard to noise have grown ever more severe, and development of an LC element having functions as a compact high performance noise filter capable of reliably removing such noise is desired.
One example of this type of LC element is an LC noise filter disclosed in Japanese Patent Application Laid-Open No 3-259608. In the case of this LC noise filter, the L and C components exist as distributed constants, and compared to an integrated constant type LC filter, favorable attenuation response can be obtained over a relatively wide band.
However, this LC filter comprises a capacitor type conductor formed on one surface of an insulation sheet and an inductor type conductor formed on the other surface. Manufacturing the filter involves folding over this insulator sheet, which is among the processes that add to manufacturing complexity.
Also, wiring is required when directly inserting this LC filter into an IC or LSI power supply or signal line, thus necessitating time and labor for installing the components.
In addition, since this LC filter is formed as a discrete component, inclusion in an IC or LSI circuit, i.e., insertion into the internal wiring of an IC, LSI or other device is nearly impossible.